Field of the Invention
The present invention relates to an image blur correction technique of an image capturing apparatus for correcting an image blur generated at the time of capturing a panning shot.
Description of the Related Art
Conventionally, a technique called panning shot capturing is known as a photography technique that represents a sense of speed of a moving object. This photography technique is intended to obtain images in which the moving object remains stationary while the background is blurred by a photographer panning the camera along with the motion of the object. At the time of panning shot capturing, the photographer needs to pan the camera along with the motion of the object. However, it is often the case that if the panning speed is too high or too low, a difference occurs between the moving speed of the object and the panning speed, resulting in images in which the object is blurred.
To address this, Japanese Patent Laid-Open No. 4-163535 proposes a method for correcting an object blur by moving an image capturing unit or part of an optical system of a lens during exposure based on “the relative object angular velocity with respect to the image capturing apparatus calculated before exposure” and “the angular velocity of the image capturing apparatus during exposure obtained from an angular velocity sensor”. The relative object angular velocity with respect to the image capturing apparatus is calculated from “the amount of movement of the object on the image plane detected from temporally consecutive images” and an output of “the angular velocity sensor”.
However, with the conventional technique disclosed in Japanese Patent Laid-Open No. 4-463535 mentioned above, in the case of a relativity large object, blur may be corrected at a position other than the position intended by the photographer. FIG. 17 is a schematic view of a train moving from the right toward the left as viewed from the photographer, and it is known that the angular velocity varies at three points (A, B and C) as viewed from the photographer. FIG. 18 is a graph plotted based on the results obtained by sampling the angular velocity at the three points shown in FIG. 17 for a predetermined period of time. The horizontal axis indicates time, the time increasing from the left to the right. The vertical axis indicates angular velocity, the angular velocity increasing upward from the bottom. As can be seen from FIG. 18, the object angular velocity varies depending on which portion of the object is used to calculate the angular velocity at a given time.